1. Field of the Invention
This invention relates to a method for testing electrical properties of a silicon single crystal and more particularly to a method for evaluating dielectric breakdown voltage of the silicon oxide film grown on the surface of a polished wafer derived from the Czochralski (CZ) method or the floating zone (FZ) method by subjecting the single crystal derived therefrom to chemical treatments and visual inspection.
2. Description of the Prior Art
Heretofore, as means for evaluating the quality of a silicon semiconductor single crystal rod which has been pulled up by the Czochralski method or the floating zone pulling method, the so-called evaluation of oxide film dielectric breakdown voltage which comprises preparing a silicon polished wafer (PW wafer) from the single crystal rod, causing the silicon wafer to form an oxide film on the surface thereof, attaching a polysilicon electrode to the silicon wafer, applying a bias voltage thereto, and determining the dielectric breakdown voltage of the oxide film has been practised. This method has been recognized as one of the important testing techniques because it permits substantially equivalent simulation of the formation of a device on a silicon wafer and allows determination of the question as to whether or not the wafer manifests a suitable quality during the manufacture of a device using the wafer.
The evaluation of oxide film dielectric breakdown voltage mentioned above, however, entails such problems as (1) inability to effect this evaluation until after the PW wafer has been prepared, (2) inevitable consumption of enormous time during the process of evaluation, and (3) necessitation of an expensive apparatus for evaluation, for example.
This invention has as an object thereof the provision of a method which is capable of quickly and inexpensively effecting equivalent evaluation of the oxide film dielectric breakdown voltage of a wafer cut out of a given grown semiconductor single crystal without requiring preparation of a PW wafer for the evaluation.
The other objects and characteristic features of the present invention will become apparent to those skilled in the art as the disclosure is made in the following description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.